orderedmap
v2.1.1
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Persistent ordered mapping from strings
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OrderedMap
Persistent data structure representing an ordered mapping from strings to values, with some convenient update methods.
This is not an efficient data structure for large maps, just a minimal helper for cleanly creating and managing small maps in a way that makes their key order explicit and easy to think about.
License: MIT
Reference
The exported value from this module is the class OrderedMap
,
instances of which represent a mapping from strings to arbitrary
values.
OrderedMap.from
(value: ?Object | OrderedMap) → OrderedMap
Return a map with the given content. If null, create an empty map. If
given an ordered map, return that map itself. If given an object,
create a map from the object's properties.
Methods
Instances of OrderedMap
have the following methods and properties:
get
(key: string) → ?any
Retrieve the value stored under key
, or return undefined when
no such key exists.
update
(key: string, value: any, newKey: ?string) → OrderedMap
Create a new map by replacing the value of key
with a new
value, or adding a binding to the end of the map. If newKey
is
given, the key of the binding will be replaced with that key.
remove
(key: string) → OrderedMap
Return a map with the given key removed, if it existed.
addToStart
(key: string, value: any) → OrderedMap
Add a new key to the start of the map.
addToEnd
(key: string, value: any) → OrderedMap
Add a new key to the end of the map.
addBefore
(place: string, key: value: string, value: any) → OrderedMap
Add a key after the given key. If place
is not found, the new
key is added to the end.
forEach
(f: (key: string, value: any))
Call the given function for each key/value pair in the map, in
order.
prepend
(map: Object | OrderedMap) → OrderedMap
Create a new map by prepending the keys in this map that don't
appear in map
before the keys in map
.
append
(map: Object | OrderedMap) → OrderedMap
Create a new map by appending the keys in this map that don't
appear in map
after the keys in map
.
subtract
(map: Object | OrderedMap) → OrderedMap
Create a map containing all the keys in this map that don't
appear in map
.
toObject
() -> Object
Return an object that has the same key/value pairs as the map
.
size
: number
The amount of keys in this map.